All eight episodes from the ninth series of the BBC's political espionage drama following a team of officers in MI5. This series finds the team reeling after the explosion at the hotel at the end of the previous series. However, they are soon back in action, tracking Somalian AQ terrorist Abib (Peter Bankole) on a lethally-loaded boat headed to Plymouth from Tangier. Meanwhile, Lucas (Richard Armitage)'s identity is brought into question as unwanted elements from his past resurface.